Benefits of Investment Casting over Sand Casting.
1，With investment casting, wax patterns can be made in virtually any form—without tapers and without affecting the quality of the final product. Ceramic molds are also very hard, which create smooth surfaces with low tolerances—often with very thin walls. Once any gates and sprue have been removed, many products don't require any additional labor for treatment or finishing Sand molds must be pulled apart to remove a pattern before pouring. To ensure a proper mold, a pattern needs to be designed with tapers, or drafts, to minimize friction—and to prevent the sand mold from being disrupted—when the sections are split apart. Because sand molds are comprised of two pieces, the final product will always have a parting line, which may need to be ground away once cooled.
2，Internal cavities can also be a challenge for Sand Casting
, which rely on the use of cores. A core is a preformed shape that is inserted into a mold to form the interior of the part not in contact with the mold's surface. Depending on the shape and complexity of a core—which can be a single component or an assembly of multiple cores—it can be time-consuming to form and secure within a mold.,
3，It's also worth noting that sand molds, even with synthetic additives and high compaction, can't achieve the hardness of ceramic. As a result, sand-casted surfaces often have higher tolerances and require machine grinding to achieve a finished surface. Depending on the final product application, and the scope of production, this may not be ideal.